The present invention relates to fire suppression systems and, more particularly to a coupling for securing a fire suppression supply conduit to a supporting surface through which the fire suppression supply conduit extends. The conduit fitting produces a seal around the fire suppression supply conduit and prevents flames from penetrating the supporting surface from a fire that may occur, for example, under or in the hoods and ducts in commercial kitchen ventilation systems.
The benefits of automatic fire suppression systems to suppress or prevent the spread of fire in environments such as a commercial kitchen have long been known. Such common automatic sprinkler systems include dry chemical (sodium bicarbonate), liquid agent (metallic salt solutions), CO.sub.2, and water sprinklers. Among the features which these systems have in common is the use of a supply conduit to convey a fire suppressant medium to the discharge nozzle. In a typical application such as for a kitchen grill where the chances of a fire occurring are considerably above average, the automatic system is normally installed with the individual nozzle heads mounted in the high risk areas, that is, the exhaust hoods positioned over the grill, or in the ducts which are connected to the exhaust hoods. Such a typical automatic system has a source of fire suppressant medium which is remotely located from sprinkler heads or discharge nozzles which dispense the fire suppressant medium. The supply conduit normally passes through the wall of a hood or duct to connect the supply of fire suppressant to the sprinkler heads. In such an arrangement, the supply conduit passes through the wall of the exhaust hood or duct at a penetration point. In the event of a fire in the exhaust hood or duct, it is important for the prevention of spread of the fire and that the fire be contained within the hood or duct and not be allowed to escape through the penetration points of the supply conduits. Further, it is important to contain any grease ladened air or liquid grease within the ventilating system structure such that this material cannot leak to the back side of the hood during the normal course of ventilator system operation. Such leakage, were a fire to occur, could cause a fire to be communicated outside the confines of the ventilating system, e.g., on the back side of the hood, by autoignition of the grease on the hot ventilating system surfaces. Various solutions have been proposed to solve this problem. For example, a welded joint, or a joint providing a permanent weld-like seal, have been utilized at such penetration points, and are now commonly required by building codes.
The current practice of welding may be an expedient means of addressing this problem and conforming with the assorted building code requirements, but it presents various disadvantages. For example, the installation of a welded joint is normally labor intensive, time consuming, and may result in damage or distortion to the surrounding hood or duct areas. Moreover, repair and/or replacement of the seal is normally extremely difficult, if not impossible.
Therefore, it has long been known that it would be desirable to have a fire resistant support or fitting which supports the conduit passing through the supporting surface, but in a manner which does not have the attendant shortcomings of the prior art devices and practices.